1. Field of Invention
The present invention relates in general to automatic door operating devices and more particularly to the door operating devices of a type that is suitable for automatically opening and closing a back door that is pivotally connected to the open back of a wheeled motor vehicle.
2. Description of the Related Art
Hitherto, various types of automatic door operating devices have been proposed and put into practical use particularly in the field of the wheeled motor vehicles. One of such devices is shown in Laid-open Japanese Patent Application (Tokkai) 2001-253241.
The door operating device of this publication comprises two substantially same units, each including an electric motor mounted to the vehicle body, a pinion gear driven by the motor, a rack bar meshed with the pinion gear, a rail member extending upward from the motor to appropriately guide a movement of an upper part of the rack bar, and a connecting rod having one end pivotally connected to the upper part of the rack bar and the other end pivotally connected to a pivotal back door of the vehicle. Thus, upon energization of the motor, the rack bar is moved upward or downward thereby pivoting the back door in an opening or closing direction through the connecting rod.
In the door operating device of the publication, the pivotal connection between the rack bar and the connecting rod is made through a so-called xe2x80x9cball-socket typexe2x80x9d joint structure which includes a ball that is possessed by the rack bar and a socket that is possessed by the connecting rod and universally slidably holds the ball.
However, due to the nature of the ball-socket type joint structure, the applicants have found a possibility of xe2x80x9cout of jointxe2x80x9d of the structure especially when an abnormally big force is suddenly applied to the structure from the back door in a direction to pull the ball and the socket apart.
Accordingly, an object of the present invention is to provide an automatic door operating device which is free of the above-mentioned drawback.
That is, it is an object of the present invention to provide an automatic door operating device which assures a durable pivotal connection between the rack bar and the connecting rod, which can keep their pivotal connection even when an abnormally big force is applied to them from the back door.
According to a first aspect of the present invention, there is provided an automatic door operating device for a motor vehicle that has a door pivotally connected to a body of the vehicle, the device comprising a drive unit mounted to the vehicle body and including an electric motor and a pinion gear driven by the electric motor; a rack bar meshed with the pinion gear; a rail member mounted to the vehicle body, the rail member having a longitudinally extending guide slot formed therethrough; a connecting rod having one end pivotally connected to the door; and a joint/slider unit that pivotally connects an end of the rack bar to the other end of the connecting rod while being slid in and along the guide slot of the rail member, wherein the joint/slider unit includes a bolt member passing through the guide slot and including first and second sections which are respectively projected into one and the other sides with respect to the rail member, the first section being held by the end of the rack bar and the second section being pivotally held by the other end of the connecting rod; a first slider disposed on the first section of the bolt member and slidably contacting one surface of the rail member; a second slider disposed on the second section of the bolt member and slidably contacting the other surface of the rail member; and a universal joint structure disposed between the second slider and the other end of the connecting rod to permit a pivoting of the connecting rod relative to the bolt member in universal directions.
According to a second aspect of the present invention, there is provided an automatic door operating device for a motor vehicle that has a door pivotally connected to a body of the vehicle, the device comprising a drive unit mounted to the vehicle body and including an electric motor and a pinion gear driven by the electric motor; a rack bar meshed with the pinion gear and having upper and lower ends; a rail member mounted to the vehicle body, the rail member having a longitudinally extending guide slot formed therethrough and elongate flanges between which the guide slot is defined; a connecting rod having an upper end pivotally connected to the door; a bolt member passing through the guide slot of the rail member and including first and second sections which are respectively projected into one and the other sides with respect to the rail member, the first section being held by the upper end of the rack bar and the second section being pivotally held by a lower end of the connecting rod; a first slider disposed on the first section of the bolt member and slidably contacting one surface of the rail member; a second slider disposed on the second section of the bolt member and slidably contacting the other surface of the rail member and inner surfaces of the elongate flanges of the rail member; a rod holder disposed in an opening formed in the lower end of the connecting rod; a concave portion possessed by the rod holder; and a convex portion possessed by the second slider and intimately and slidably engaged with the concave portion.
According to a third aspect of the present invention, there is provided an automatic door operating device for a motor vehicle that has a door pivotally connected to a body of the vehicle, the device comprising a drive unit mounted to the vehicle body and including an electric motor and a pinion gear driven by the electric motor; a rack bar meshed with the pinion gear and having upper and lower ends which are angled to each other by a given degree; a rail member mounted to the vehicle body, the rail member having a longitudinally extending guide slot formed therethrough and elongate flanges between which the guide slot is defined, the rail member being bent by a given angle at a generally middle portion thereof; a connecting rod having an upper end pivotally connected to the door; a bolt member passing through the guide slot of the rail member and including first and second sections which are respectively projected into one and the other sides with respect to the rail member, the first section being held by the upper end of the rack bar and the second section being pivotally held by a lower end of the connecting rod; a first slider disposed on the first section of the bolt member and slidably contacting one surface of the rail member; a second slider disposed on the second section of the bolt member and slidably contacting the other surface of the rail member and inner surfaces of the elongate flanges of the rail member; a rod holder disposed in an opening formed in the lower end of the connecting rod; a concave portion possessed by the rod holder; and a convex portion possessed by the second slider and intimately and slidably engaged with the concave portion.